Dafydd ap Gwilym's famous Welsh poem Yr Wylan talks about the beauty of a seagull, the sea, and his love.
Did he see the seagull at Conwy, where I'm from? He wrote around 1360AD, when the Castle was only fifty years old, so, as a Welshman, he would have been excluded.
The full text of the poem is here in Welsh, and you can hear it read in Welsh and English here on You Tube. There's a fair few translations, like this one.